Device for magnifying displacement of piezoelectric element or the like and method of producing same

Abstract

A device for magnifying displacement of a piezoelectric element adapted to be displaced by application of voltage thereto, comprising a frame extending substantially parallel to a direction of displacement of the piezoelectric element; a movable member fixed to a first end of the piezoelectric element with respect to the direction of displacement; a first mount surface formed on said frame and extending substantially parallel to the direction of displacement; a second mount surface formed on the movable member and extending substantially parallel to the direction of displacement, which second mount surface is opposed to the first mount surface; a first leaf spring mounted at a first end portion on the first mount surface and extending substantially parallel to the direction of displacement; a second leaf spring mounted at a first end portion on the second mount surface and extending substantially parallel to the direction of displacement; and a rolling member fixed to second end portions of the first and second leaf springs, wherein when the piezoelectric element is displaced, the second leaf spring is displaced along the first leaf spring through the movable member to roll the rolling member.

What is claimed is: 
     
       1. A device for magnifying displacement of a piezoelectric element adapted to be displaced by application of voltage thereto, comprising: a frame extending substantially parallel to a direction of displacement of said piezoelectric element, said piezoelectric element being mounted on said frame;   a movable member fixed to one end of said piezoelectric element with respect to said direction of displacement and adapted to be displaced in a direction substantially parallel to said frame;   a first mount surface formed on said frame and extending substantially parallel to said direction of displacement;   a second mount surface formed on a surface of said movable member which faces said first mount surface and extending substantially parallel to said direction of displacement, said second mount surface facing said first mount surface;   a first leaf spring mounted at a first end portion thereof on said first mount surface and extending substantially parallel to said direction of displacement;   a second leaf spring mounted at a first end portion thereof on said second mount surface and extending substantially parallel to said direction of displacement, said second leaf spring being positioned adjacent to said first leaf spring; and   a rolling member fixed to second end portions of said first and second leaf springs, wherein when said piezoelectric element is displaced, said second leaf spring is displaced along said first leaf spring through said movable member to roll said rolling member.   
     
     
       2. The device as defined in claim 1, wherein respective surfaces of said first and second leaf springs are in contact with each other under an inoperative condition of said piezoelectric element. 
     
     
       3. The device as defined in claim 1, wherein said first mount surface is located at an end portion of an end surface of said frame, and said second mount surface is located on an end surface of said movable member offset from a center line of said piezoelectric element to said frame. 
     
     
       4. The device as defined in claim 3, wherein said frame has a substantially L-shaped configuration as viewed from a side thereof such that said substantially L-shaped configuration is comprised of a vertical portion extending substantially parallel to the direction of displacement of said piezoelectric element and a base portion projecting laterally from said vertical portion for supporting one end of said piezoelectric element with respect to the direction of displacement, and wherein said first leaf spring is fixed to an end surface of said vertical portion of said frame, and said second leaf spring is fixed to the end surface of said movable member opposed to said end surface of said vertical portion. 
     
     
       5. The device as defined in claim 1, wherein said first and second leaf springs include respective deformable portion facing each other, and said deformable portions are formed at their facing surfaces with respective noncontact portions for inhibiting contact between said deformable portions. 
     
     
       6. The devices as defined in claim 5, wherein said deformable portions of said first and second leaf springs are formed with recesses on opposite surfaces to said facing surfaces. 
     
     
       7. The device as defined in claim 5, wherein said first and second leaf springs are formed from a single spring member in which a split groove is formed which extends from a first end of said spring member toward a second end thereof, and said rolling member is integrally connected to said second end. 
     
     
       8. The device as defined in claim 7, wherein said first leaf spring is fixed to an end surface of said frame extending substantially parallel to said piezoelectric element, and said second leaf spring is fixed to an end surface of said movable member opposed to said end surface of said frame and offset from a center line of said piezoelectric element to said frame. 
     
     
       9. The device as defined in claim 7, wherein said split groove comprises a cutout formed from said first end of said spring member toward said second end thereof. 
     
     
       10. The device as defined in claim 7, wherein a head portion of said spring member formed at said second end thereof without said split groove forms at least a part of said rolling member, thus integrally forming the leaf springs with said at least a part of said rolling member. 
     
     
       11. The device as defined in claim 7, wherein said split groove comprises a space defined by bending said spring member into a U-shaped configuration. 
     
     
       12. The device as defined in claim 1, wherein said first and second leaf springs are formed on their opposite surfaces with grooves to form thin-walled portions opposed to each other at positions of said grooves. 
     
     
       13. The device as defined in claim 12, wherein said grooves are arranged at intervals in the direction of displacement of said piezoelectric element. 
     
     
       14. The device as defined in claim 1, wherein said first and second leaf springs have narrow portions each having a width smaller than that of said fixed ends, respectively. 
     
     
       15. A device for magnifying displacement of a piezoelectric element adapted to be displaced .[.be.]. .Iadd.by .Iaddend.application of voltage thereto, comprising: a frame extending substantially parallel to a direction of displacement of said piezoelectric element, said piezoelectric element being mounted on said frame;   a movable member fixed to one end of said piezoelectric element with respect to said direction of displacement;   a first mount .[.surfaced.]. .Iadd.surface .Iaddend.formed on said frame and extending substantially parallel to said direction of displacement;   a second mount surface formed on a surface of said movable member and extending substantially parallel to said direction of displacement, and second mount surface facing said first mount surface;   a first leaf spring mounted at a first end portion thereof on said first mount surface and extending substantially parallel to said direction of displacement;   a second leaf spring mounted at a first end portion thereof on said second mount surface and extending substantially parallel to said direction of displacement;   a rolling member fixed to second end portions of said first and second leaf springs, wherein when said piezoelectric element is displaced, said second leaf spring is displaced along said first leaf spring through said movable member to roll said rolling member; and   an elastically deformable connecting member extending along said piezoelectric element on an opposite side of said frame with respect to said movable member and connecting said movable member with a base portion of said frame, wherein when said piezoelectric element is displaced, said movable member is displaced substantially parallel to the direction of displacement against the elasticity of said connecting member to curve said second leaf spring relative to said first leaf spring and thereby roll said rolling member.   
     
     
       16. The device as defined in claim 15, wherein said connecting member is formed independently of said frame and said movable member, and is fixed to said frame and said movable member. 
     
     
       17. The device as defined in claim 15, wherein said connecting member is formed by a plate-like member having a width substantially parallel to a direction of thickness of said leaf springs and having a small sectional area in a direction perpendicular to the width of said leaf spring. 
     
     
       18. The device as defined in claim 17, wherein a sectional area at end portions of said connecting member to be fixed to said movable member and said frame are larger than a sectional area at an intermediate portion between said fixed end portions. 
     
     
       19. The device as defined in claim 15, wherein said connecting member normally applies a compression force to said piezoelectric element. 
     
     
       20. A device for magnifying displacement of a piezoelectric element adapted to be displaced by application of voltage thereto, comprising: a frame extending substantially parallel to a direction of displacement of said piezoelectric element, said piezoelectric element being mounted on said frame;   a movable member fixed to one end of said piezoelectric element with respect to said direction of displacement;   a first mount surface formed on said frame and extending substantially parallel to said direction of displacement;   a second mount surface formed on a surface of said movable member and extending substantially parallel to said direction of displacement, said second mount surface facing said first mount surface;   a first leaf spring mounted at a first end portion thereof on said first mount surface and extending substantially parallel to said direction of displacement;   a second leaf spring mounted at a first end portion thereof on said second mount surface and extending substantially parallel to said direction of displacement;   a rolling member fixed to second end portions of said first and second leaf springs, wherein when said piezoelectric element is displaced, said second leaf spring is displaced along said first leaf spring through said movable member to roll said rolling member; and   a quadri-hinged parallel link mechanism provided between said frame and said movable member for maintaining parallelism of said movable member to the direction of displacement of said piezoelectric element.   
     
     
       21. The device as defined in claim 20, wherein said quadri-hinged parallel link mechanism comprises a pair of first and second link plates each comprising a pair of vertical parallel link portions fixed to a side surface of said frame and a side surface of said movable member, a pair of horizontal parallel link portions extending between said vertical parallel link portions, and four elastically deformable hinge portions connecting said vertical parallel link portions with said horizontal parallel link portions. 
     
     
       22. The device as defined in claim 21 further comprising a connecting portion for connecting one of said vertical parallel link portions of said first link plate with .Iadd.an .Iaddend.opposite .[.on.]. one of said vertical parallel link portions of said second link plate. 
     
     
       23. The device as defined in claim 15 further comprising a quadri-hinged parallel link mechanism provided between said frame and said movable member for maintaining parallelism of said movable member to the direction of displacement of said piezoelectric element. 
     
     
       24. The device as defined in claim 1, wherein said rolling member comprises a base member fixed to second end positions of said first and second leaf springs; and an arm connected to said base member, said base member being formed with a recess for inserting a firm end of said arm. 
     
     
       25. The device as defined in claim 1, wherein said rolling member is formed with a recess for inserting the second end portions of said first and second leaf springs. 
     
     
       26. The device as defined in claim 10, wherein said rolling member comprises said head portion and an arm connected to said head portion, said head portion being formed with a recess for inserting a first end of said arm. 
     
     
       27. The device as defined in claim 12, wherein a spacing between said rolling member and said frame and between said rolling member and said movable member is greater than a width of said grooves. 
     
     
       28. The device as defined in claim 27, wherein said first leaf spring is fixed by brazing to said first mount surface of said frame, and said second leaf spring is fixed by brazing to said second mount surface of said movable member. .Iadd.29. A displacement magnifying device comprising: a frame;   an elastic member having first and second connection portions, said first connecting portion being secured to said frame;   an electro-distortion element having first and second opposite ends and responsive to selective application of an electrical voltage thereto to undergo displacement, said first end being connected to said frame, said second end being connected to said second connecting portion; and   an elastically deformable restricting member for restricting displacement of said electro-distortion element, said elastically deformable restricting member having first and second opposite restriction ends, said first restriction end being secured to a first connection part connecting said frame to said first end of said electro-distortion element, said second restriction end being secured to a second connection part connecting said second end of said electro-distortion element to said second connecting portion of said elastic member. .Iaddend. .Iadd.30. A displacement magnifying device comprising:   a frame;   a rolling member;   an electro-distortion element having a first end connected to said frame and responsive to selective application of an electrical voltage thereto to undergo longitudinal expansion and contraction;   a first resilient member having a first end connected to a second opposite end of said electro-distortion element and a second end connected to said rolling member;   a second resilient member disposed in a substantially parallel relationahip to said first resilient member and having a first end connected to said frame and a second end connected to said rolling member; and   a restricting member, having first and second portions, extending transversely to said first and second resilient members and fixedly connected at said first portion to said electro-distortion element and at said second portion to said frame, said restricting member restricting said electro-distortion element from displacement away from said frame in a direction substantially perpendicular to said first and second resilient members. .Iaddend. .Iadd.31. A printing head comprising a frame, a plurality of impact printing wires constituting a wire-dot matrix and a plurality of displacement magnifying devices respectively corresponding to, and for selectively driving, said respective impact printing wires, each of said displacement magnifying devices comprising:   a rolling member to which the respective one of said impact printing wires is connected;   an electro-distortion device having a first end connected to said frame and responsive to selective application of an electrical voltage thereto to undergo longitudinal expansion and contraction;   a first resilient member having a first end connected to the second end of said electro-distortion device and thereby to said frame and a second end connected to said rolling member;   a second resilient member disposed in substantially parallel relationship to said first resilient member and having a first end connected to said frame and a second end connected to said rolling member so that the extent of longitudinal expansion and contraction of said electro-distortion device in response to the selective application of an electrical voltage thereto is enlarged by said rolling member and transmitted thereby to said impact printing wire; and   a restricting member having first and second, opposite ends, extending transversely to said first and second resilient member and fixedly connected at the first end to said electro-distortion device and at the second, opposite end to said frame and thereby extending therebetween and restricting said electro-distortion device from displacement away from said frame in a direction substantially perpendicular to said first and second resilient members. .Iaddend. .Iadd.32. A printing head as set forth in claim 31, wherein said frame is substantially L-shaped having a base and a side wall extending substantially perpendicular to said base, said electro-distortion device has one end connected to said base and the other end connected to said resilient member, and said restricting member has one end connected to said side wall and the other end connected to said electro-distortion device in the vicinity of the other end thereof. .Iaddend. .Iadd.33. A printing head as set forth in claim 31, wherein said impact printing wire is connected to said rolling member at a first position thereof;   said second end of said first reislient member is connected to said rolling member at a second position thereof; and   said second end of said second resilient member is connected to said rolling member at a third position thereof, said first and third positions being disposed oppositely, relatively to said second position, so that the extent of longitudinal expansion and contraction of said electro-distortion device is enlarged by said rolling member and transmitted to said impact printing wire. .Iaddend. .Iadd.34. A printing head as set forth in claim 33, wherein a distance from said first position to said second position is larger than a distance from said second position to said third position. .Iaddend. .Iadd.35. A printing head comprising a frame, a plurality of impact printing wires constituting a wire-dot matrix and a plurality of displacement magnifying devices respectively corresponding to, and for selectively driving, said respective impact printing wires, each of said displacement magnifying devices comprising:   a rolling member to which the respective one of said impact printing wires is connected;   an electro-distortion device having a first end connected to said frame and responsive to selective application of an electrical voltage thereto to undergo longitudinal expansion and contraction;   a first resilient member having a first end connected to the second end of said electro-distortion device and thereby to said frame and a second end connected to said rolling member;   a second resilient member disposed in substantially parallel relationship to said first resilient member and having a first end connected to said frame and a second end connected to said rolling member so that the extent of longitudinal expansion and contraction of said electro-distortion device in response to the selective application of an electrical voltage thereto is enlarged by said rolling member and transmitted thereby to said impact printing wire; and   a restricting member connected between said electro-distortion device and said frame for restricting said electro-distortion device from displacement in a direction substantially perpendicular to said first and second resilient members. .Iaddend. .Iadd.36. A device for magnifying displacement of an electro-distortion element adapted to be displaced by application of voltage thereto, comprising:   a frame extending substantially parallel to a direction of displacement of said electro-distortion element, said electro-distortion element being mounted on said frame;   a movable member fixed to one end of said electro-distortion element with respect to said direction of displacement;   a first mount surface formed on said frame and extending substantially parallel to said direction of displacement;   a second mount surface formed on a surface of said movable member and extending substantially parallel to said direction of displacement, said second mount surface facing said first mount surface;   a first elastic member, mounted at a first end portion thereof on said first mount surface and extending substantially parallel to said direction of displacement;   a second elastic member mounted at a first end portion thereof on said second mount surface and extending substantially parallel to said direction of displacement;   a rolling member fixed to second end portions of said first and second elastic members, wherein when said electro-distortion element is displaced, said second elastic member is displaced along said first elastic member through said movable member to roll said rolling member; and   an elastically deformable connecting member connected between said electro-distortion element and said frame to maintain said movable member substantially parallel with said frame when said electro-distortion element is displaced, such that said movable member is displaced substantially parallel to the direction of displacement against the elasticity of said connecting member to move said second elastic member relative to said first elastic member and thereby roll said rolling member. .Iaddend. .Iadd.37. The device as defined in claim 36, wherein said connecting member is formed independently of said frame and said movable member, and is fixed to said frame and said movable member. .Iaddend. .Iadd.38. The device as defined in claim 36, wherein said connecting member is formed by an elongate member having a width substantially parallel to a direction of thickness of said elastic members and having a small sectional area in a direction perpendicular to the width of said elastic members. .Iaddend. .Iadd.39. The device as defined in claim 38, wherein a sectional area at end portions of said connecting member to be fixed to said movable member and said frame are larger than a sectional area at an intermediate portion between said fixed end portions. .Iaddend. .Iadd.40. The device as defined in claim 36, wherein said connecting member normally applies a compression force to said electro-distortion element. .Iaddend. .Iadd.41. A device as defined in claim 36, wherein said first and second elastic members are leaf springs. .Iaddend. .Iadd.42. A device as defined in claim 36, wherein said connecting member extends substantially parallel to said first and second elastic members. .Iaddend. .Iadd.43. A device as defined in claim 36, wherein said connecting member extends substantially perpendicular to said first and second elastic members. .Iaddend. .Iadd.44. A device for magnifying displacement of an electro-distortion element adapted to be displaced by application of voltage thereto, comprising:   a frame extending substantially parallel to a direction of displacement of said electro-distortion element, said electro-distortion element being mounted on said frame;   a movable member fixed to one end of said electro-distortion element with respect to said direction of displacement;   a first mount surface formed on said frame and extending substantially parallel to said direction of displacement;   a second mount surface formed on a surface of said movable member and extending substantially parallel to said direction of displacement, said second mount surface facing said first mount surface;   a first elastic member mounted at a first end portion thereof on said first mount surface and extending substantially parallel to said direction of displacement;   a second elastic member mounted at a first end portion thereof on said second mount surface and extending substantially parallel to said direction of displacement;   a rolling member fixed to second end portions of said first and second elastic members, wherein when said electro-distortion element is displaced, said second elastic member is displaced along said first elastic member through said movable member to roll said rolling member; and   an elastically deformable mechanism provided between said frame and said movable member for maintaining parallelism of said movable member to the direction of displacement of said electro-distortion element. .Iaddend. .Iadd.45. A device as defined in claim 44, wherein said first and second elastic members are leaf springs. .Iaddend. .Iadd.46. A device as defined in claim 44, wherein said deformable mechanism is an elongate member extending substantially parallel to said first and second elastic members. .Iaddend. .Iadd.47. A device as defined in claim 44, wherein said deformable mechanism is a quadri-hinged parallel link. .Iaddend. .Iadd.48. The device as defined in claim 47, wherein said quadri-hinged parallel link comprises a pair of first and second link plates each comprising a pair of vertical parallel link portions fixed to a side surface of said frame and a side surface of said movable member, a pair of horizontal parallel link portions extending between said vertical parallel link portions, and four elastic deformable hinge portions connecting said vertically parallel link portions with said horizontal parallel link portions. .Iaddend. .Iadd.49. The device as defined in claim 48, further comprising a connecting portion for connecting one of said vertical parallel link portions of said first link plate with an opposite one of said vertical parallel link portions of said second link plate. .Iaddend.